Intangible Assets (Details) - USD ($)	3 Months Ended		12 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Jul. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 82,995,000		$ 82,995,000
Accumulated amortization	64,362,000		62,986,000
Net carrying amount	18,633,000		$ 20,009,000
Amortization of intangibles	1,376,000	$ 1,561,000
Amortization expense - year one	4,962,000
Amortization expense - year two	4,782,000
Amortization expense - year three	4,782,000
Amortization expense - year four	862,000
Amortization expense - year five	$ 862,000
Technologies
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	13 years		12 years 1 month 6 days
Gross carrying amount	$ 47,370,000		$ 47,370,000
Accumulated amortization	39,846,000		39,266,000
Net carrying amount	$ 7,524,000		$ 8,104,000
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	10 years		10 years
Gross carrying amount	$ 29,831,000		$ 29,831,000
Accumulated amortization	21,718,000		20,981,000
Net carrying amount	$ 8,113,000		$ 8,850,000
Trademarks and other
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	20 years		20 years
Gross carrying amount	$ 5,794,000		$ 5,794,000
Accumulated amortization	2,798,000		2,739,000
Net carrying amount	$ 2,996,000		$ 3,055,000